The present invention relates to catheter and introducer needle assemblies. In medicine, such catheter and introducer needle assemblies are used to place a catheter properly into the vascular system of a patient. Once in place, catheters such as intravenous (or “IV”) catheters may be used to infuse fluids including normal saline, medicinal compounds, and/or nutritional compositions (including total parenteral nutrition, or “TPN”) into a patient in need of such treatment. Catheters additionally enable the removal of fluids from the circulatory system and monitoring of conditions within the vascular system of the patient.
One type of commonly-used catheter is a peripheral intravenous catheter. These short, indwelling intravenous catheters are often used to provide an entry route for medications, fluid for hydration, and in some cases, for parenteral feeding, into a patient. Such catheters are generally short in length, ranging from about one-half to about three inches in length, and are generally made of flexible biocompatible materials. In some cases, these catheters additionally include a radiopaque compound such as barium sulfate to allow the location of the catheters to be tracked once inside the body.
Peripheral IV catheters are often provided as “over-the-needle” catheters mounted over an introducer needle with a sharp distal tip. This sharp tip often includes a bevel intended to be oriented away from the patient's skin during penetration of the skin. A portion of the catheter including at least the distal tip of the catheter securely grips the outside of the needle to prevent catheter peelback during insertion of the catheter into the circulatory system of the patient. Although several techniques for placing such catheters are practiced in the art, many generally include the step of inserting at least a portion of the needle into the target vessel and then sliding the catheter over the needle into place.
The medical worker then attempts to verify proper placement of the catheter within the blood vessel. Catheter and introducer needle assemblies have been provided that include means for verifying proper placement of the catheter in a blood vessel. One such means is a “flashback chamber” that is viewable to the clinician during installation. This chamber receives a small quantity of blood when a vessel is entered, thus allowing observation of blood in the chamber to be an indicator of successful entry into a vessel. Flashback notification may also be provided by providing a notch in the introducer needle a distance from the sharp distal tip of the needle in a region that is housed within the catheter. Blood flashback may then be observed at the notch and regions near it within the catheter when the catheter is at least somewhat transparent.
Once placement of the needle has been confirmed, the user may temporarily occlude flow to the blood vessel, remove the needle, leaving the catheter in place, and attach a device to the catheter for fluid removal, input, or to seal the catheter. This process has been somewhat difficult in practice since many placement sites simply do not allow easy occlusion of the target vessel. Additionally, even when such occlusion is achieved, it may be imperfect, thus resulting in blood leaking from the catheter, endangering the medical personnel employing it.
“Needle shields” or needle-shielding devices have also been used with catheters. These devices are designed such that when the needle is withdrawn from the patient, the needle tip will be trapped/captured within the needle shield. The purpose of these needle shield devices is to house the tip of the needle in a secure location so that the needle tip will not accidentally be injected/impaled into the nurse, the doctor, etc.
Catheter and introducer needle assemblies have thus been provided in the art that provide a variety of seals or “septa” for preventing outflow of fluid during and following removal of the introducer needle. These structures are generally elastomeric plates designed to closely conform to the shape of a needle during storage and use to prevent leaking, then to seal upon removal of the needle. These septa need to be elongated in needles with flashback notches so as to encapsulate the notch and needle tip during needle removal in order to prevent the unwanted escape of blood. This elongation of the septa increases the amount of friction placed on the needle, the amount of effort needed to remove it, and the potential of damaging the product. In order to overcome this, septa have been developed that include an internal cavity that has an internal diameter slightly larger than that of the needle used. This results in the needle contacting the septum only in regions outside of this cavity, reducing the surface area in contact with the septum.
However, there is a need in the art for a new type of septa that will engage/interconnect with the needle shield to ensure that the needle will not prematurely separate from the catheter device. Such a device is disclosed herein in the present embodiments.